The U.S. Centers for Disease Control and Prevention's vaccine advisory committee is set to meet on March 18 to 19, an update on the agency's website showed on Tuesday, after its previously scheduled session in February was canceled.

The Advisory Committee on Immunization Practices (ACIP), which makes recommendations for who should get which vaccines, was originally scheduled to meet from February 25 to 27, but a spokesman for the Department of Health and Human Services told Reuters it was canceled.

The move had deepened uncertainty around decisions under U.S. Health Secretary Robert F. Kennedy Jr., who has sought sweeping changes to the national vaccination policy, including dropping broad recommendations for six childhood shots and cutting mRNA-based vaccine research funding.

The committee's recommendations historically have been used to guide U.S. health insurance coverage, state policies on vaccines needed for schools and how physicians advise parents and patients. The panel faced multiple revamps last year, after Kennedy fired all 17 of its members in June.

The American College of Obstetricians & Gynecologists (ACOG) said it was withdrawing as a liaison organization to the advisory committee, citing concerns about recent changes that include its reconstitution and the removal of ACOG experts from ACIP work groups.

ACOG president Steven Fleischman said these changes represent "a fundamental departure from the scientific rigor and impartiality that have been the hallmark of this committee for 60 years."

Several medical organizations have also filed a lawsuit, challenging policies adopted under Kennedy that they say would lower vaccination rates.

Earlier this month, major U.S. medical groups asked a federal judge to block the administration from implementing new guidance that cuts the number of vaccines routinely recommended for children and to bar Kennedy's handpicked vaccine advisory panel from holding its next meeting